Various medical devices have been disclosed which are adapted to either dispense fluids onto body tissues, suction fluids from body tissues, or to perform a combination of dispensing and suctioning fluids. Examples of such prior disclosure are provided in an overview fashion below.
Various known suction devices have been adapted for different medical applications. In such suction devices, several valve structures have been used to control and vary the amount of suction. These known valve mechanisms for medical suction devices generally: adjust the fluid communication with vacuum directly to the working tip, or alternatively, adjust the proportion of vacuum pressure directed to a vent pathway in parallel with the suction tip. Often, the specific valve structures for adjusting fluid passageways for suction are referred to as stopcock (1,2, or 3-way), gate, pinch, trumpet, or venturi valves.
Examples of suction devices using valve structures which adjust fluid communication directly with the vacuum source are disclosed in U.S. Pat. Nos.: 3,645,497; 4,487,600; 4,504,266. Such devices which also combine fluid dispensing include U.S. Pat. Nos. 2,812,765; 3,208,145; 4,696,669; 4,776,840; 4,891,044; 5,061,180; 5,186,714; 5,295,956; 5,476,450; 5,603,700. Furthermore, such devices that adjust suction in a variably-controlled amount are disclosed in U.S. Pat. Nos. 3,645,497; 4,776,840; and 5,368,560.
One type of mechanism such as that just described is a "pinch valve", such as is disclosed in U.S. Pat. Nos. 4,696,669 and 5,295,956. U.S. Pat. No. 5,295,956 to Bales et al. discloses a pinch valve providing variable suction control in a hand-held endoscopic suctioning device. In this device, a suction passageway is held closed by a spring-loaded hook (preferably plastic) which is attached to a trigger button. Upon "pulling" the trigger, the attached hook relieves the compression of the flexible tubing, opening the suction passageway. Hence, depending on the displacement of the trigger button, the suction may be controlled.
Similar to pinch valves, trumpet valves also affect fluid communication between the vacuum source and the working tip. Rather than constrict the passageway, however, the trumpet valve functions by controlling the degree of blockage in the suction passageway; thereby adjusting the amount of fluid flowing through the suction passageway.
For example, U.S. Pat. No. 3,645,497 to Nyboer discloses a hand-held variable controlled suction device adapted for use in dental applications. The passageway connecting the vacuum source to the working tip is entirely blocked by a thin plate when the user desires no vacuum pressure. Alternatively, to increase vacuum pressure at the working tip, the user can slide the plate in variable amounts; resulting in an increase or decrease in the amount of fluid flow through the passageway.
A hand-held medical evacuator and irrigation device is disclosed in U.S. Pat. No. 4,776,840 to Freitas. Basically, two ports exist at the working end. One port is directly connected to a vacuum source and the other port either dispenses solution or provides a vacuum. In addition to the constant vacuum port, a second, and adjustable, suction is created by pressing a conveniently located plunger with the user's thumb. By depressing the plunger, the vacuum source communicates with the dispensing port and simultaneously prevents any backflow from contaminating the fluid reservoir. Furthermore, the plunger is tapered which, depending on its displacement, adjusts fluid flow (suction) between the vacuum source and the dispensing port.
In addition to trumpet-type valves, suction may be adjusted by changing the proportion of vacuum pressure directed to a vent pathway in parallel to the working suction tip. These structures are herein referred to as "venturi"-type structures. When the vent pathway is covered, vacuum pressure at the working tip is greatest and all suction is through the passageway. On the other hand, when the vent pathway is open, suction is primarily through the vent pathway and the working tip sees little suction. Furthermore, the amount of vacuum pressure may be adjusted in proportion to the amount of fluid flow through the vent pathway. However, when the working tip is occluded, this control is generally believed to have little sensitivity because most suction flows through the vent pathway.
Examples of venturi-type valves used in medical suction devices are described in the following U.S. Pat. Nos. 3,469,582; 3,625,221; 4,356,823; 4,445,517; 4,617,013; 4,699,138; 4,857,047; 5,024,615; 5,226,877. These devices, which also dispense solution, are disclosed in U.S. Pat. Nos.: 4,617,013; 4,857,047; and 5,226,877. In U.S. Pat. No. 3,625,221, adjustable venturi suction is disclosed and in U.S. Pat. Nos. 5,419,769 and 3,469,582, a venturi suction actuates another member to communicate fluid flow between the vacuum source and the working tip.
In particular, U.S. Pat. No. 5,024,615 to Buchel discloses a suction device used for surgical operations with a venturi-type valve used to adjust vacuum pressure. The amount of fluid flow through the vent pathway is adjusted by the user's finger-tip and accordingly, the vacuum pressure at the working tip of the device is adjusted.
In addition to trumpet and venturi-type mechanisms described above, another device structure creating mild suction is disclosed in U.S. Pat. No. 5,300,022 to Klapper et al. Here, however, suction is created as an irrigating solution flows across a drainage (vacuum inlet) port at the working tip. Due to the cone shaped structure, the irrigating solution is deflected downward away from the drainage port, creating a mild venturi suction.
In addition to the cited references provided above, further disclosures of suction devices are disclosed in U.S. Pat. Nos. 1,206,126; 3,065,749; 3,949,748; 4,573,979; 4,904,328; 5,024,654; 5,145,367; 5,348,542; 5,433,705.
There is still a need for a medical suctioning device that provides for the controllable selection of varied levels of suction at a working tip.
There is also still a need for a medical suctioning device which inversely and reciprocally adjusts the proportion of applied suction between a suction pathway in a working tip and a vent pathway.